A proposition asserts something. That assertion is performed by the symbol which stands for the act of consciousness. That which accounts for assertion seeming so different from other sorts of signification is its volitional character.

Every assertion is an assertion that two different signs have the same object.

1895-6 [c.] | That Categorical and Hypothetical Propositions are one in essence, with some connected matters | CP 2.334-335

In every assertion we may distinguish a speaker and a listener. The latter, it is true, need have only a problematical existence, as when during a shipwreck an account of the accident is sealed in a bottle and thrown upon the water. The problematical “listener” may be within the same person as the “speaker”; as when we mentally register a judgment, to be remembered later. If there be any act of judgment independent of any registry, and if it have any logical significance (which is disputable), we may say that in that case the listener becomes identical with the speaker.

The assertion consists in the furnishing of evidence by the speaker to the listener that the speaker believes something, that is, finds a certain idea to be definitively compulsory on a certain occasion. There ought, therefore, to be three parts in every assertion, a sign of the occasion of the compulsion, a sign of the enforced idea, and a sign evidential of the compulsion affecting the speaker in so far as he identifies himself with the scientific intelligence.

Let us distinguish between the proposition and the assertion of that proposition. We will grant, if you please, that the proposition itself merely represents an image with a label or pointer attached to it. But to assert that proposition is to make oneself responsible for it, without any definite forfeit, it is true, but with a forfeit no smaller for being unnamed. Now an ex post facto law is forbidden by the Constitution of the United States of America, but an ex post facto contract is forbidden by the constitution of things. A man cannot promise what the past shall have been, if he tries. It is evident that to guarantee that, if a piece of work has not already been done right, one will pay for it, and to guarantee that, if it shall be found not to have already been done right, one will pay for it, have one and the same meaning. One or other of them therefore must be an elliptical or otherwise unliteral expression, or else both are so. But nobody will maintain that to promise to pay for the work, if it shall be ascertained not to have been already done right, really means to promise to so pay, if it shall in fact not have been already done right, whether it be ascertained or not. It would be equally absurd to say that there was any third meaning which should have reference to an unascertained past. It follows, then, that to contract to pay money if something in the past has been done or not done can only mean that the money shall be paid if it is ascertained that the event has happened or has not happened. But there would be no reason why the literal sense should not be understood if it made any sense. Hence there can be no meaning in making oneself responsible for a past event independent of its future ascertainment. But to assert a proposition is to make oneself responsible for its truth. Consequently, the only meaning which an assertion of a past fact can have is that, if in the future the truth be ascertained, so it shall be ascertained to be. There seems to be no rational escape from this.

…an act of assertion supposes that, a proposition being formulated, a person performs an act which renders him liable to the penalties of the social law (or, at any rate, those of the moral law) in case it should not be true, unless he has a definite and sufficient excuse…

…it is a fairly easy problem to analyze the nature of assertion. To find an easily dissected example, we shall naturally take a case where the assertive element is magnified, – a very formal assertion, such as an affidavit. Here a man goes before a notary or magistrate and takes such action that if what he says is not true, evil consequences will be visited upon him, and this he does with a view to thus causing other men to be affected just as they would be if the proposition sworn to had presented itself to them as a perceptual fact.

We thus see that the act of assertion is an act of a totally different nature from the act of apprehending the meaning of the proposition and we cannot expect that any analysis of what assertion is (or any analysis of what judgment or belief is, if that act is at all allied to assertion), should throw any light at all on the widely different question of what the apprehension of the meaning of a proposition is.

What is the difference between making an assertion and laying a wager? Both are acts whereby the agent deliberately subjects himself to evil consequences if a certain proposition is not true. Only when he offers to bet he hopes the other man will make himself responsible in the same way for the truth of the contrary proposition; while when he makes an assertion he always (or almost always) wishes the man to whom he makes it to be led to do what he does. Accordingly in our vernacular “I will bet” so and so, is the phrase expressive of a private opinion which one does not expect others to share, while “You bet” ___ is a form of assertion intended to cause another to follow suit.

The man is a symbol. Different men, so far as they can have any ideas in common, are the same symbol. Judgment is the determination of the man-symbol to have whatever interpretant the judged proposition has. Assertion is the determination of the man-symbol to determining the interpreter, so far as he is interpreter, in the same way.

A dicent is not an assertion, but is a sign capable of being asserted. But an assertion is a dicent. According to my present view (I may see more light in future) the act of assertion is not a pure act of signification. It is an exhibition of the fact that one subjects oneself to the penalties visited on a liar if the proposition asserted is not true.

To assert a proposition means to accept responsibility for it, so that if it turns out ill, or as Mr. Schiller says (by implication) unsatisfactory, in a certain way which we need not define, but which is called proving to be false, he who has asserted it regrets having done so.

…an assertion belongs to the class of phenomena like going before a notary and making an affidavit, executing a deed, signing a note, of which the essence is that one voluntarily puts oneself into a situation in which penalties will be incurred unless some proposition is true. One may maintain that every proposition involves an assertion. Very likely that may be true as a psychological truth; but if so the element of assertion is frequently altogether or in great degree inhibited and disavowed. I have nothing further to say about assertion.

1906 [c.] | On the System of Existential Graphs Considered as an Instrument for the Investigation of Logic | MS [R] 499

…assertion does not add a new element of thought. For an assertion is not a thought but a deed. If one goes before a notary and takes one’s affidavit to a statement, that is nothing but highly emphatic assertion.

What is the nature of assertion? We have no magnifying-glass that can enlarge its features, and render them more discernible; but in default of such an instrument we can select for examination a very formal assertion, the features of which have purposely been rendered very prominent, in order to emphasize its solemnity. If a man desires to assert anything very solemnly, he takes such steps as will enable him to go before a magistrate or notary and take a binding oath to it. Taking an oath is not mainly an event of the nature of a setting forth, Vorstellung, or representing. It is not mere saying, but is doing. The law, I believe, calls it an “act.” At any rate, it would be followed by very real effects, in case the substance of what is asserted should be proved untrue. This ingredient, the assuming of responsibility, which is so prominent in solemn assertion, must be present in every genuine assertion. For clearly, every assertion involves an effort to make the intended interpreter believe what is asserted, to which end a reason for believing it must be furnished. But if a lie would not endanger the esteem in which the utterer was held, nor otherwise be apt to entail such real effects as he would avoid, the interpreter would have no reason to believe the assertion. Nobody takes any positive stock in those conventional utterances, such as “I am perfectly delighted to see you,” upon whose falsehood no punishment at all is visited. At this point, the reader should call to mind, or, if he does not know it, should make the observations requisite to convince himself, that even in solitary meditation every judgment is an effort to press home, upon the self of the immediate future and of the general future, some truth. It is a genuine assertion, just as the vernacular phrase represents it; and solitary dialectic is still of the nature of dialogue. Consequently it must be equally true that here too there is contained an element of assuming responsibility, of “taking the consequences.”

A Proposition is nearly the same as an “Assertion.” The distinction which I use the two words to mark is that an Assertion includes no more than it is the intention of the Utterer to declare, while the Proposition includes all that he does declare, which is inevitably considerably more than he intends.

1913 | Analysis of the Trustworthiness of the Different Kinds of Reasonings | MS [R] 680:22-3

…throughout this essay the word “assertion” will be used to mean a certain kind of communication, and so to denote a performance requiring the coöperation of two parties (though not necessarily two different persons, since one person, for example, may write a memorandum for his own future information); one of these parties, who shall be called the utterer, by an exertion of will renders the other party, who shall be called the interpreter, sensible of certain signs by which he must recognize the fact that the utterer has willed to assert; and in the great majority of cases he will regard it as a real fact. The signs of which the interpreter becomes sensible may be indirect; that is, signs of signs; by which means ever so complex an assertion may be made in a single sign through a “code.”

Citation

‘Assertion’. Term in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/term/assertion, 03.09.2019.